Differential slack line carrier



May 21, 1963 Filed Feb. 8, 1960 FIG.|

3 Sheets-$heet 1 l INVENTOR.

2 MERE/LL L4), H/TE (jggmu ky ATTORNE Y5 May 21, 1963 M. w. HlTE 3,090,497

DIFFERENTIAL SLACK LINE CARRIER May 21, 1963 M. w. HlTE DIFFERENTIAL SLACK LINE CARRIER 3 Sheets-Sheet 3 Filed Feb. 8, 1960 INVENTOR. fRR/LL UJ-HITE' M Y RQ c: if l w,

ATTORNEYS llii ington Filed Feb. 8, 1960, Ser. No. 7,348 Claims. (Cl. 212-126) This invention relates to slack line carriers adapted to be employed in suspension type cable-way systems, and namely that type of system in which a carriage tracks along a main cable suspended between two separated towers, one of which is a control tower, being moved along the length of said main cable by a second endless cable commonly referred to as a haul cable. A third cable, commonly termed a hoist cable, extends from the control tower to a sheave on the carriage. Between this sheave and a terminal anchor also provided on the carriage or anchor tower the hoist cable presents a depending loop. A load-carrying sheave occupies the bight of this loop. When free of a load, the section of the hoist cable which lies between the carriage and the control tower becomes slack. The slack line carriers of the present invention track on the main cable and give support to such slack section of the hoist cable. Systems of the described character customarily are employed either with a button-line pick-up or provide a means by which differential driving energy is passed from the slack line to a live sheave tracking on the main cable. In either case it is .desired to distribute several slack line carriers more or less evenly between the carriage and the control tower or the anchor tower, as the case may be.

The present invention purposes to provide a perfected system of said differentially-driven type employing a live sheave, and particularly aims to provide a drive arrangement of comparatively simple and inexpensive construction and one in particular which is positive in nature.

The foregoing and other more particular objects and advantages in view will appear and be understood in the course of the following description and claims. The invention consists in the novel construction and in the adaptation and combination of parts hereinafter described and claimed.

In the accompanying drawings:

FIGURE 1 is a fragmentary side elevational View portraying a slack line carrier constructed to embody the preferred teachings of the present invention, the vantage point being shown at 11 in FIG. 2.

FIG. 2 is a transverse vertical sectional view on line 22 of FIG. 1.

FIG. 3 is a horizontal sectional view drawn to an enlarged scale on line 3-3 of FIG. 1.

FIG. 4 is a fragmentary longitudinal vertical sectional view drawn to an enlarged scale on line 4-4 of FIG. 2.

FIG. 5 is a horizontal sectional view drawn to an enlarged scale on line 55 of FIG. 1; and

FIG. 6 is a diagrammatic view exemplifying the differential drives which would be provided in a cable hoist system employing three slack carriers between the carriage and the tower, either anchor or control, as the case might be.

The slack line carrier of the present invention has a main frame fabricated from top and bottom sets 1011 and 1213, respectively, of vertically disposed cheekplates suitably cross-connected and each rigidly secured to an intervening horizontal yoke 14. The yoke occupies a position moderately close to the head end of the frame, and its closed end projects a substantial distance beyond the cheek-plates. At a level intermediate the height of the frame each cheek-plate has a horizontally extending beam 15 rigidly secured thereto, and at each end of these beams the same are joined by a cross-member faced with IiydWAh? Patented May 21, P563 a rubber bumper 16. A sub-frame fabricated from spaced apart vertical side bars 17 and 18 hangs from the lower end of the main frame and gives support to a sheave 20 over which the hoist cable 21 passes. The other two cables, and namely the main cable and the haul cable, are designated by 22 and 23, respectively.

Two horizontal sheave-carrying shafts, as 24 and 25, are journaled for rotation in the cheek-plates of the main frame adjacent the upper end and the lower end, respectively, of said frame. The two sheaves, as 26 and 27, occupy positions between the plates. Each of the shafts have one end prolonged axially beyond the concerned cheek-plate. Pulleywheels, as 28 and 2h, are fixed to these shaft ends, and a nominally slack endless belt or belts 30 passes around such pulley-wheels, with the slack normally taken up by an idler 31 carried by a forked arm 32 pivoted at 33 from one of the two beams 15. A spring 34 yieldingly urges the idler against the belt. The free end of the forked arm 32 is linked by a rod 35 to one end 36 of a plain lever fulcrumed at 37 to the same beam 15 which carries the forked arm. In a manner hereinafter described the other end 38 of said lever is arranged to be engaged in the operation of the system by a toe prolongation 40 presented by a next adjacent slack carrier or the carriage, as the case may be. Several such slack carriers are employed in a cableway system. Such toe prolongation and the lever occur upon opposite ends of each of said slack carriers.

The haul cable 23 is adapted to overlie the sheave 27, riding in the groove of the latter. Two complementing sheaves 41 and 42 bear upon the cable from above, one lying to the front and the other to the rear of the transverse vertical plane occupied by the sheave 27. The function of such sheaves 41 and 42 is to exert such pressure upon the cable as to establish a non-slip friction drive from the cable to the sheave 27. To this end each sheave 41 and 42 is journal-mounted on a pin 43 extending between a pair of elbowed levers 44 of the second order. The root arms of these elbowed pairs of levers extend fore-and-aft horizontally in opposite directions from a fixed fulcrum 45 common to both. The free ends of the pairs of levers are yieldingly urged directively from one another by a compression spring 46 shown by dotted lines in FIG. 1.

As can be best seen from an inspection of FIG. 2, gusset-reinforced laterally projecting flanges 50 are provided at the base end of the cheek-plates 10-11 and at the head end of the cheek-plates 1213. The side arms 49 of the yoke 14 are sectionally of a channel shape to present flanges 51 which are bolted to the flanges 50. The span between the side arms 49 is considerably greater than the span between the cheek-plates. In the spaces thus provided there is received a respective one of tworeach arms 52 pivoted for vertical swing motion from a shaft 53 extending transversely between the two yoke arms 49 adjacent the cross arm 48 of such yoke. The free ends of the reach arms are connected by a wrist pin 54. A spring 55 surrounding a guide rod 59 presses. against said pin to yieldingly urge the free ends of the reach arms in an upward direction. Said reach arms 52, and the elbowed levers 44, each function as a swing frame in that the same are carried by the main frame for vertical swing motion about a respective transverse horizontal axis, the reach arms about the center of shaft 53 as an axis and said elbowed levers about the center of pin 45 as an axis.

Between the shaft 53 and the wrist pin 54 the reach arms are traversed by a shaft 56 on which there is journaled a sheave 57 arranged to bear from below upon the main cable. A gear wheel 58 is boltably secured to one face of such sheave 57. This gear wheel is. meshed by a gear wheel 60 journalcd for rotation on the pivot shaft 53. A pulley wheel 61 is also journaled for rotation on said pivot shaft, occupying a position to' the side of the sheave -7 opposite from the gear wheel. The pulley wheel 61 and the gear wheel 60 are both fast to a common hub 62 so as to rotate in unison. 63 denotes an endless drive belt running from pulley wheel 61 to a pulley wheel 64 fast to the sheave 26. The ratio between pulley wheels 61 and 64, and between gear wheels 58 and 61), is l to l in each instance. Sheaves 26 and 57, which have a corresponding diameter, are consequently each positively driven at a corresponding rim speed and each takes a driving purchase upon the main cable. slippage as between the main cable 22 and the two sheaves between which it travels is substantially eliminated.

As the slack line carriers of the present invention travel along the main cable 22 by the friction drive of the sheaves 26 and 57, the same are caused to be difierentially driven by the respective belt 30 .driven so that each carrier in the series travels only at a proportioned speed. Let it be assumed, for example, that the slack line 21 takes its support from a series of three carriers. For any given distance traversed by the carriage, the #1, #2, and #3 carriers (considered in respect of proximity to the carriage) will travel, respectively, three-fourths, one-half, and one-fourth this distance. To accomplish this end a ratio of 1 to 3 is provided as between the diameters of the sheave 26 and the sheave 27 of the #1 carrier. A l to 1 ratio is provided in the #2 carrier, and a 3 to 1 ratio in the #3 carrier. This can be readily seen by an inspection of FIG. 6 wherein the carriage side of three said carriers is presumed to lie at the right-hand side of the figure.

It is believed that the invention will have been clearly understood from the foregoing detailed description of the now-preferred illustrated embodiment of the invention. It is my intention that no limitations are to be implied and that the hereto annexed claims be given a scope fully commensurate with the broadest interpretation to which the employed language admits.

What I claim, is: a

1. In a cable system of the described character in which a main carriage tracks upon a main cable extending between cable towers, is caused to travel along said main cable by a haul cable, and has a hoist cable for supporting a load from the carriage, a carrier for distributing slack in the hoist cable comprising a main frame, two vertically spaced swing-frames carried by the main frame for swing movement about transverse horizontal axes, a driving set of principal and secondary complementary sheaves one carried by the main frame and the other by one of said swing-frames so as to both track upon the main cable one from above and one from below in opposing relation, a haul-powered set of principal and secondary complementary sheaves one carried by the main frame and the other by the other swing-frame so as to both track upon the haul cable one from above and one from below in opposing relation, a respective spring acting upon each of said swing-frames to yieldingly urge the, secondary sheave which is carried thereby toward the related principal sheave so that the main cable will be securely gripped by the driving set of sheaves and the haul cable securely gripped by the haul-powered set of sheaves, complementary pulley wheels secured so as to rotate in unison one with one and the other with the other of said two principal sheaves, an endless drive belt trained about said pulley wheels, a belt tightener for said drive belt, a pulley wheel journaled to turn about the swing axis of the first said swing-frame, a gear fast to the last-named pulley wheel and meshing a gear fast to the secondary sheave of the driving set of sheaves, and an endless drive belt trained about the last-named pulley wheel and a pulley wheel secured so as to rotate in unison with said principal sheave of the driving set of sheaves.

2. The carrier recited in claim 1 characterized in that the main frame is comprised of upper and lower pairs of separated cheek plates and having a horizontal yoke presenting side arms which are secured between the upper and the lower cheek plates,'the span between said side arms exceeding that of the cheek plates so as to provide inwardly facing pockets of substantial depth at each side of the frame, the first-named swing-frame comprising two spaced-apart pivotally mounted reach arms each of which occupies a respective one of the two pockets.

3. Structure according to claim 2, the spring which acts upon said first-named swing-frame exerting its force upon the free ends of said reach arms.

4. In a cable system of the described character in which a main carriage tracks upon a main cable extending be.- tween cable towers, is caused to travel along said main cable by a paralleling haul cable, and has a hoist cable for supporting a load from the carriage, a carrier for distributing slack in the hoist cable comprising a main frame, a vertically movable swing-frame pivoted to the main frame for vertical swin motion about a transverse horizontal axis, a driving set of principal and secondary sheaves the former carried by the main frame and the latter by the swing-frame so as to both track upon the main cable in substantially the same transverse vertical plane one from above and one from below in opposing relation, a haul-powered set of one principal sheave and two secondary sheaves vertically spaced from the principal sheaves and similarly arranged to track from opposite sides upon the haul cable, said last-named secondary sheaves being spaced apart longitudinally of the haul cable, said principal sheave of the haul-powered set being carried by the main frame, a respective one of two vertically movable swing-frames pivoted to the main frame tor vertical swing motion about a transverse horizontal axis and each having a respective one of said last-named two secondary sheaves carried thereby at its free end, respective springs yieldingly urging the principal and secondary sheaves of said two sets directively toward one another so that the main cable will be securely gripped by the driving set of sheaves and the haul cable securely gripped by the haul-powered set of sheaves, complementary pulley wheels secured so as to rotate in unison one with one and the other with the other of said two principal sheaves, an endless drive belt trained about said pulley wheels, a belt tightener for said drive 'belt, a pulley wheel journaled to turn about the swing axis of the first said swing-frame, a gear fast to the last-named pulley wheel and meshing a gear fast to the secondary sheave of the driving set of sheaves, and an endless drive belt trained about the last-named pulley wheel and a pulley wheel secured so as to rotate in unison with said principal sheave of the driving set of sheaves.

5. A carrier according to claim 4, the swing-frames for the secondary sheaves of the haul-powered set of sheaves comprising two elbowed levers one arm of each of which extends horizontally one in a forward direction and the other in an aft direction from a common swing center and the other armof each of which extends vertically from the free end of the horizontal arm in a direction away from the haul cable, the secondary sheaves of said haul-powered set of sheaves being mounted at the approximate juncture of said horizontal and vertical arms of the elbowed levers, the spring for said haul-powered set of sheaves being a compression spring lying between the free ends of the vertical arms of said elbowed levers and acting thereon to yieldingly spread the same.

References Cited in the file of this patent UNITED STATES PATENTS 548,973 Dusedau Oct. 29, 1895 901,021 Miller Oct. 13, 1908 1,120,145 Horton Dec. 8, 1914 2,741,372 Richards Apr. 10, 1956 

1. IN A CABLE SYSTEM OF THE DESCRIBED CHARACTER IN WHICH A MAIN CARRIAGE TRACKS UPON A MAIN CABLE EXTENDING BETWEEN CABLE TOWERS, IS CAUSED TO TRAVEL ALONG SAID MAIN CABLE BY A HAUL CABLE, AND HAS A HOIST CABLE FOR SUPPORTING A LOAD FROM THE CARRIAGE, A CARRIER FOR DISTRIBUTING SLACK IN THE HOIST CABLE COMPRISING A MAIN FRAME, TWO VERTICALLY SPACED SWING-FRAMES CARRIED BY THE MAIN FRAME FOR SWING MOVEMENT ABOUT TRANSVERSE HORIZONTAL AXES, A DRIVING SET OF PRINCIPAL AND SECONDARY COMPLEMENTARY SHEAVES ONE CARRIED BY THE MAIN FRAME AND THE OTHER BY ONE OF SAID SWING-FRAMES SO AS TO BOTH TRACK UPON THE MAIN CABLE ONE FROM ABOVE AND ONE FROM BELOW IN OPPOSING RELATION, A HAUL-POWERED SET OF PRINCIPAL AND SECONDARY COMPLEMENTARY SHEAVES ONE CARRIED BY THE MAIN FRAME AND THE OTHER BY THE OTHER SWING-FRAME SO AS TO BOTH TRACK UPON THE HAUL CABLE ONE FROM ABOVE AND ONE FROM BELOW IN OPPOSING RELATION, A RESPECTIVE SPRING ACTING UPON EACH OF SAID SWING-FRAMES TO YIELDINGLY URGE THE SECONDRY SHEAVE WHICH IS CARRIED THEREBY TOWARD THE RELATED PRINCIPAL SHEAVE SO THAT THE MAIN CABLE WILL BE SECURELY GRIPPED BY THE DRIVING SET OF SHEAVES AND THE HAUL CABLE SECURELY GRIPPED BY THE HAUL-POWERED SET OF SHEAVES, COMPLEMENTARY PULLEY WHEELS SECURED SO AS TO ROTATE IN UNISON ONE WITH ONE AND THE OTHER WITH THE OTHER OF SAID TWO PRINCI- 